The present invention relates to magnetic tape drives such as those utilized with computers and other data processing equipment. More particularly the present invention relates to a magnetic tape drive which has a low profile configuration and in which the supply reel can be loaded through a front slot. The supply reel is automatically centered and secured on the supply hub and the free end of the tape is automatically threaded and secured to the take-up reel by vacuum action.
Magnetic tape drives have long been used for storage and retrieval of information, particularly in connection with high speed digital computers. The tape supply reel is normally secured on a supply hub and the free end of the tape is threaded along a predetermined path over a read/write head. The tape end is then secured to a take-up reel mounted on a take-up hub. The supply and take-up hubs have individual drive motors. In response to various commands sent to the magnetic tape drive, the reels are simultaneously rotated clockwise or counter-clockwise so that various blocks of data on the tape may be read or written by the head.
Generally, in order to facilitate loading of a magnetic tape drive, that is the placement of the supply and take-up reels on their respective hubs and the threading of the tape from one reel to the other, magnetic tape drives are usually installed in an upright position, the reels and head assembly being exposed for access. Such tape drives have several drawbacks. First of all, they require a considerable amount of space and this limits the packaging arrangement in many instances. Since the reels and head assembly are exposed, it is usually necessary to improve the overall appearance of the tape drive by means of trim, covers and other cosmetic features, which add to the cost of the apparatus. In many installations, the mechanism is protected by doors, which are often transparent, leaving the mechanism exposed and thus subject to aesthetic treatment. Furthermore, the loading of many such magnetic tape drives involve a tedious manual effort. Such manual loading also presents a risk of tape contamination and tape damage as a result of operator handling.
It would therefore be advantageous to have a tape drive unit which would fit into a minimum amount of space, be concealed in use so as not to acquire cosmetic trim, be easy to load and unload, and reduce the risk of tape contamination or damage. One slot loaded, low profile magnetic tape drive is described in U.S. Patent Application Ser. No. 66,792, filed on or about Aug. 15, 1979 and owned by the assignee of the present invention. That unit is constructed in a horizontal configuration to fit in a drawer or similar low profile installation, the tape being loaded and unloaded through a front slot without the need for access through the mechanism. The take-up reel has a vacuum action to retain the tape and it is mounted on an arm which swings back in the enclosure and pulls the tape over a guide and a head array. The supply reel is simultaneously retracted so that the tape and reel are fully enclosed.
Low profile magnetic tape drives which have heretofore been commercially manufactured by others have basically been upright units which have been turned on their side so that complete access to their top has been required. A number of auto-threading magnetic tape drive units have been commercially manufactured by International Business Machines, Inc., and others. Typically they have been upright units which have used a combination of gravity action and a plurality of high pressure jets to guide the tape from the supply reel, past the head assembly, to the take-up reel. Some have utilized a vacuum actuated take-up reel for assisting in the attachment of the free end of the tape thereto. Such units typically require a complex array of manifolds, air conduits, and nozzles. The automatic threading action is subject to malfunction if one or more of the jets is not precisely aimed at the tape to guide it, for example, around a guide roller. Variations in air pressure can also cause malfunctions. Exemplary of such auto-threading magnetic tape drives are U.S. Pat. No. 3,863,863 and the MOD 12 MTU manufactured by Wangco, Inc., 5404 Jandy Place, Los Angeles, Calif. , 90066. Auto-threading magnetic tape drives heretofore known have generally utilized compatible cartridges which surround the supply reel and aid in the automatic threading of the free end of the tape. Generally all such units have been constructed to accommodate one reel size, namely the standard ten inch reel.